The shock was not so much at the front end of the first Olympic women's keirin final, but at the rear.

Victoria Pendleton rebounded emphatically from the nightmare of blowing Great Britain's opportunity in the team sprint on the opening night to win the gold medal.

But far less believable was the fact that Anna Meares, the reigning world champion in the eight-lap discipline, who arrived in London intent on upstaging Britain's best female cyclist at her home Games, was only spared the ultimate belittlement of last place by a photo finish.

As Pendleton, jubilant and at the peak of her sporting powers despite being days away from retirement, waved at an adoring crowd, it was difficult not to wonder whether this was two wins sewn up in one.

Launching a devastating attack on a pack of six riders in the last two laps on Friday night, she won a final while simultaneously crushing her fiercest rival ahead of their anticipated clash in the individual sprint over the coming days.

The Australians in the house sat with jaws dropped, at once admiring Pendleton's speed but shocked by how Meares - who made her big move with three laps to go - had lost.

Doing her best to fight her welling eyes, Meares would not concede that this result meant anything more than what it was on paper - a loss in one event that she had designs on winning. She had to pull herself together, see her husband, re-focus, lest another race she travelled to win in London end in ruin.

"It was a bit tough," Meares began after composing herself sufficiently in the pits to reflect publicly on a race gone terribly wrong.

"I thought I moved my position up earlier than what I probably would have liked, given the quality of some of the riders in the field. I thought that would be quite an advantageous position to be in, on the front, and fend off the attacks as opposed to having to come from behind.

"I think the plan was a good one, but I just didn't execute it very well tonight and I found myself in a reactive position as opposed to a proactive one.

"I was too slow, I didn't have enough speed at the bell. I got myself squeezed quite significantly at the 200 (mark) and...I couldn't do anything."

China's Shuang Guo, one of four former world keirin world champions in the final, claimed silver while Wai Sze Lee became the first track cyclist from Hong Kong to win a medal by taking the bronze.

"I could have really leant on Guo to try to push her out, but I didn't," Meares said, chastising herself from even going into coulda-shoulda-woulda territory.

"It definitely feels disappointing...I felt great in the semi-final and was really looking forward to putting it out there in the final but it just didn't go to my plan tonight."

Indeed, the way Pendleton and Meares had dominated the qualifying rounds only reinforced the commonly-held view that the eventual battle for gold would be between two women.

In a preview as valuable for the competitors as it was intriguing for their audience, the duo were in the same heat in the first round. While Pendleton took the honours in bout one, Meares gave the impression she had not raced to her maximum after appearing to pull up slightly once she was convinced her qualification was secured.

Separated in the second rounds, Meares dismantled her lesser rivals while Pendleton was equally decisive, leaving 2004 and 2005 world keirin champion Clara Sanchez and Guo, the 2009 world title holder in the event, in her wake.

Pendleton's blitz in the final only firmed her favouritism in the individual sprint competition where, after the qualification rounds spread over several days, she will seek to defend the Olympic crown she won in Beijing four years ago.

Meares was forced to concede defeat to the Briton on Friday night, but that was where her concessions stopped. Asked if she still believed she could win the sprint, Meares replied: "I believe I can. Absolutely. If I believed otherwise I'm out of the contest.

"The form's there, it's just the execution of the tactics that separated the two of us tonight."